1. Field of the Invention
The present invention relates to a multilayered tube comprising a saturated polyester (hereinafter referred to as PES) as the inner and the outer layers, a saponified product of ethylene-vinyl acetate copolymer (hereinafter referred to as EVOH) as the intermediate layer, and an adhesive resin (hereinafter referred to as TR) layer between the PES layer and the EVOH layer; and a multilayered container utilizing the tube; as well as methods of producing the tube and the container.
2. Description of the Prior Art
PES, represented by polyethylene terephthalate (hereinafter referred to as PET) is, because of its high transparency, heat resistance, mechanical properties, and so on, widely used not only for fibers and films but for containers for beverages and foods or as films for food packaging. In the case where PES is used for containers for foods or films for food packaging, though it has by itself a certain degree of gas barrier property and so suitable for preserving foods, there is still expected a higher gas barrier property depending on the type of foods or beverages to be filled or packed therein. Thereupon, attempts have been made to have EVOH, which resin has a higher gas barrier property, laminate onto PES to obtain tubes, blow bottles and films having multilayered structures. For example, JPA's Nos. 108162/1978, 77144/1981, 128516,1982, U.S. Pat. No. 4,504,531, and JPA No. 199237/1984 disclose tubes and blow bottles which have laminted the two resins. However, when a composite of PES and EVOH is formed into a biaxially drawn multilayered container, there is observed in the appearance of the container (bottle) an abnormal nonuniformity looking like streaks to make the bottle unsatisfactory. FIG. 10 is an elevation of a bottle of bad appearance, showing streaky nonuniformities. This streakiness, S (hereinafter referred to simply as streaks), markedly deteriorates the commercial value of the bottle, and the bottle can not stand comparison with monolayered bottles of PET which are sold commercially.